Q.
Somato-dissociative states are well-known. However, if one experiences an "out-of-body" state
for weeks, is that considered to be a more
serious condition? How do clinicians measure the
seriousness of dissociative states?

A.
What you are describing is usually termed a depersonalization experience.
Depersonalization experiences appear to be quite common; e.g., about half of
all adults may have experienced a single, brief episode, usually under
extreme stress or danger. (In younger populations, transient
depersonalization experiences may be associated with substance abuse or
intoxication). These transient states (lasting minutes, hours, or perhaps a
day or two) do not necessarily indicate a psychiatric disorder.

However,
when depersonalization becomes persistent or recurrent, is accompanied by
significant distress or impairment in function; and is not due to some other
psychiatric or medical disorder, we usually diagnose Depersonalization
Disorder (DD). This may involve "...a persistent or recurrent...feeling of
detachment or estrangement from one's self...the individual may feel like an
automaton or...[like]...an outside observer of one's mental processes, one's
body, or parts of one's body." (DSM-IV).

There have not been a great many
studies of DD. However, Simeon et al (Am J Psychiatry 1997
Aug;154(8):1107-13) studied 19 women and 11 men with DD, using the
self-rated Dissociative Experiences Scale (DES), which is one way of gauging
severity of dissociation. An age- and sex-matched normal comparison group
was also studied. The mean age at onset of depersonalization disorder was
16.1 years (SD = 5.2). The illness had a chronic course that was usually
continuous but sometimes episodic. Severe distress and high levels of
interpersonal impairment were characteristic. Unipolar mood and anxiety
disorders were common, but none emerged as specifically related to the
depersonalization. A wide variety of co-morbid personality disorders was
noted: avoidant, borderline, and obsessive-compulsive were most common.
Although not highly traumatized, the subjects with depersonalization
disorder reported significantly more childhood trauma than the normal
comparison subjects.

DD tends to be quite refractory to treatment, though it
may respond to SSRI type medication, such as fluoxetine or sertraline.
Prolonged dissociative symptoms always raise the question of covert
neurological or medical illness, such as complex partial seizures, temporal
lobe tumor, etc. Thus, a thorough medical/neurological assessment is
indicated prior to making a final diagnosis of DD.